Diamond K-12 Fire Rescue Blades for Metal Cutting and Extraction

Diamond blades are mounted onto the blade shaft of a saw and clamped tightly into place between two collars or flanges. When power is applied to the shaft, the blade spins. The saw operator then begins pushing the blade into the material.

Now the cutting begins - but a diamond blade does not really "cut" like a knife - it grinds. Let’s look at this grinding process step by step.

Remember, the diamond segment is made up of diamond crystals embedded in a metal matrix or bond. During the factory "break in" process individual diamond crystals are exposed to the  face and sides of the diamond segment, with supporting bond tails trailing behind them. Note the direction of rotation of the blade. You can feel the diamond exposure by running your fingernail along the edge of the segment.

As the blade segment contacts the material, the exposed diamond crystals on the segment face grind through the material. The exposed crystals on the sides of the segment provide relief so that the blade will "clear" the sides of the cut.

While diamond crystals are grinding away the material, the material is wearing away the segment. The hardness of the material causes the diamonds to fracture and break apart as they cut. The abrasiveness of the material wears away the metal bond. Eventually, as the bond continues to wear, it releases the "used" diamond. Another "new" diamond then begins its grinding work.

From the first cut, this continuous exposing, grinding and wearing process continues all around the blade until the diamond segment is completely worn away. Also notice that the steel core wears thinner as the segment wears down.

When diamond blades are used to saw hard materials, (like tile, brick or cured concrete with hard aggregate) the hardness of the material will cause the exposed diamonds to fracture and break down quickly, to keep "new" sharp diamonds exposed on the segment surface.

Therefore, blades designed to cut hard materials, generally have relatively soft metal bonds. The soft bond allows the blade to cut freely and stay "sharp".

Now, for sawing relatively soft abrasive materials, (like masonry block, "green" concrete or asphalt) the metal bond must be hard. The hard bond resists the abrasion and holds the exposed diamond crystals long enough, so that they can do the maximum amount of grinding before being replaced by "new" diamonds.